1. Field of the Invention
The present invention relates to a valve timing adjusting device for an internal combustion engine.
2. Description of Related Art
A known valve timing adjusting device adjusts valve timing by changing a relative phase between two rotators, which rotate in conjunction with a crankshaft and a camshaft, with the use of a planetary mechanism (for example, as described in German Patent Gazette No. 4110195C2). In this kind of valve timing adjusting device, gear sections provided on the rotators respectively interlocked with the crankshaft and the camshaft are geared individually with two gear sections provided on a planetary rotator. Thus, a large reduction gear ratio can be obtained by a compact design. Thus, a suitable valve timing adjusting device attached to the engine is provided.
In the valve timing adjusting device of the above-described kind, a planetary carrier supporting the planetary rotator receives a radial load, which is generated by the engagement between the gear sections and is applied to the planetary rotator. A mode of receiving the radial load differs depending on the numbers of teeth, diameters and the like of the gear sections. The inventor of the present invention discovered the problem that the planetary rotator is inclined from a proper axial direction depending on the mode of receiving the load.
In a mode shown in FIG. 11, a planetary carrier 1004 supports a planetary rotator 1000 on an inner peripheral side of a tooth contact center c1 as a longitudinal center of each of geared portions of a gear section 1001 of the planetary rotator 1000 and a gear section 1003 of an interlocked rotator 1002 of a camshaft. The planetary rotator 1000 is separate from and is not supported by the planetary carrier 1004 on an inner peripheral side of a tooth contact center c2 as a longitudinal center of each of geared portions of the other gear section 1005 of the planetary rotator 1000 and a gear section 1007 of an interlocked rotator 1006 of the crankshaft. In such the mode, if moment f1·a1 produced by the radial load f1 between the gear sections 1001, 1003 becomes smaller than moment f2·a2 produced by the radial load f2 between the gear sections 1005, 1007, the planetary rotator 1000 rotates in a moment direction d of the latter moment F2·a2 and inclines.
Such the inclination of the planetary rotator can generate a thrust load between the gear sections engaged with each other and cause a fall in durability. Therefore, such the inclination is not desirable.